The following passage contains two blanks. Choose the option that can make the passage meaningful.
Beyond the _______ engineering achievement, the Apollo 8 mission also seemed to serve a meaningful purpose for society. The trip to lunar orbit allowed a devastating year to end on a hopeful note. In 1968 America _______ assassinations, riots, a bitter presidential election, and seemingly endless violence in Vietnam, and a growing protest movement against the war. And then, as if by some miracle, Americans watched a live broadcast from three astronauts circling the moon on Christmas Eve.
The context suggests that the first blank should contain an adjective that means 'great', to correspond to the engineering 'achievement'.
Astounding means impressive. Enervating means drained of energy.
Most of the options can fit the first blank to make the sentence meaningful.
The second blank should contain a verb that means 'witnessed'. This is only given by 'endured', meaning 'suffered'.
Therefore, the correct answer is option 4.